def test_locatenew_point():
"""
Tests Point class, and locate_new method in CoordSysCartesian.
"""
A = CoordSysCartesian('A')
assert isinstance(A.origin, Point)
v = a * A.i + b * A.j + c * A.k
C = A.locate_new('C', v)
assert C.origin.position_wrt(A) == \
C.position_wrt(A) == \
C.origin.position_wrt(A.origin) == v
assert A.origin.position_wrt(C) == \
A.position_wrt(C) == \
A.origin.position_wrt(C.origin) == -v
assert A.origin.express_coordinates(C) == (-a, -b, -c)
p = A.origin.locate_new('p', -v)
assert p.express_coordinates(A) == (-a, -b, -c)
assert p.position_wrt(C.origin) == p.position_wrt(C) == \
-2 * v
p1 = p.locate_new('p1', 2 * v)
assert p1.position_wrt(C.origin) == Vector.zero
assert p1.express_coordinates(C) == (0, 0, 0)
p2 = p.locate_new('p2', A.i)
assert p1.position_wrt(p2) == 2 * v - A.i
assert p2.express_coordinates(C) == (-2 * a + 1, -2 * b, -2 * c)
def test_coordinate_vars():
"""
Tests the coordinate variables functionality with respect to
reorientation of coordinate systems.
"""
A = CoordSysCartesian('A')
assert BaseScalar('Ax', 0, A, ' ', ' ') == A.x
assert BaseScalar('Ay', 1, A, ' ', ' ') == A.y
assert BaseScalar('Az', 2, A, ' ', ' ') == A.z
assert BaseScalar('Ax', 0, A, ' ', ' ').__hash__() == A.x.__hash__()
assert isinstance(A.x, BaseScalar) and \
isinstance(A.y, BaseScalar) and \
isinstance(A.z, BaseScalar)
assert A.scalar_map(A) == {A.x: A.x, A.y: A.y, A.z: A.z}
assert A.x.system == A
B = A.orient_new_axis('B', q, A.k)
assert B.scalar_map(A) == {
B.z: A.z,
B.y: -A.x * sin(q) + A.y * cos(q),
B.x: A.x * cos(q) + A.y * sin(q)
}
assert A.scalar_map(B) == {
A.x: B.x * cos(q) - B.y * sin(q),
A.y: B.x * sin(q) + B.y * cos(q),
A.z: B.z
}
assert express(B.x, A, variables=True) == A.x * cos(q) + A.y * sin(q)
assert express(B.y, A, variables=True) == -A.x * sin(q) + A.y * cos(q)
assert express(B.z, A, variables=True) == A.z
assert express(B.x*B.y*B.z, A, variables=True) == \
A.z*(-A.x*sin(q) + A.y*cos(q))*(A.x*cos(q) + A.y*sin(q))
assert express(B.x*B.i + B.y*B.j + B.z*B.k, A) == \
(B.x*cos(q) - B.y*sin(q))*A.i + (B.x*sin(q) +
B.y*cos(q))*A.j + B.z*A.k
assert simplify(express(B.x*B.i + B.y*B.j + B.z*B.k, A,
variables=True)) == \
A.x*A.i + A.y*A.j + A.z*A.k
assert express(A.x*A.i + A.y*A.j + A.z*A.k, B) == \
(A.x*cos(q) + A.y*sin(q))*B.i + \
(-A.x*sin(q) + A.y*cos(q))*B.j + A.z*B.k
assert simplify(express(A.x*A.i + A.y*A.j + A.z*A.k, B,
variables=True)) == \
B.x*B.i + B.y*B.j + B.z*B.k
N = B.orient_new_axis('N', -q, B.k)
assert N.scalar_map(A) == \
{N.x: A.x, N.z: A.z, N.y: A.y}
C = A.orient_new_axis('C', q, A.i + A.j + A.k)
mapping = A.scalar_map(C)
assert mapping[A.x] == (C.x * (2 * cos(q) + 1) / 3 + C.y *
(-2 * sin(q + pi / 6) + 1) / 3 + C.z *
(-2 * cos(q + pi / 3) + 1) / 3)
assert mapping[A.y] == (C.x * (-2 * cos(q + pi / 3) + 1) / 3 + C.y *
(2 * cos(q) + 1) / 3 + C.z *
(-2 * sin(q + pi / 6) + 1) / 3)
assert mapping[A.z] == (C.x * (-2 * sin(q + pi / 6) + 1) / 3 + C.y *
(-2 * cos(q + pi / 3) + 1) / 3 + C.z *
(2 * cos(q) + 1) / 3)
D = A.locate_new('D', a * A.i + b * A.j + c * A.k)
assert D.scalar_map(A) == {D.z: A.z - c, D.x: A.x - a, D.y: A.y - b}
E = A.orient_new_axis('E', a, A.k, a * A.i + b * A.j + c * A.k)
assert A.scalar_map(E) == {
A.z: E.z + c,
A.x: E.x * cos(a) - E.y * sin(a) + a,
A.y: E.x * sin(a) + E.y * cos(a) + b
}
assert E.scalar_map(A) == {
E.x: (A.x - a) * cos(a) + (A.y - b) * sin(a),
E.y: (-A.x + a) * sin(a) + (A.y - b) * cos(a),
E.z: A.z - c
}
F = A.locate_new('F', Vector.zero)
assert A.scalar_map(F) == {A.z: F.z, A.x: F.x, A.y: F.y}
def test_coordinate_vars():
"""
Tests the coordinate variables functionality with respect to
reorientation of coordinate systems.
"""
A = CoordSysCartesian('A')
# Note that the name given on the lhs is different from A.x._name
assert BaseScalar('A.x', 0, A, 'A_x', r'\mathbf{{x}_{A}}') == A.x
assert BaseScalar('A.y', 1, A, 'A_y', r'\mathbf{{y}_{A}}') == A.y
assert BaseScalar('A.z', 2, A, 'A_z', r'\mathbf{{z}_{A}}') == A.z
assert BaseScalar('A.x', 0, A, 'A_x',
r'\mathbf{{x}_{A}}').__hash__() == A.x.__hash__()
assert all(isinstance(_, BaseScalar) for _ in (A.x, A.y, A.z))
assert A.x * A.y == A.y * A.x
pytest.raises(TypeError, lambda: BaseScalar('Ax', 0, 1, ' ', ' '))
pytest.raises(ValueError, lambda: BaseScalar('Ax', 5, A, ' ', ' '))
assert A.scalar_map(A) == {A.x: A.x, A.y: A.y, A.z: A.z}
assert A.x.system == A
assert A.x.diff(A.x) == 1
B = A.orient_new_axis('B', q, A.k)
assert B.scalar_map(A) == {
B.z: A.z,
B.y: -A.x * sin(q) + A.y * cos(q),
B.x: A.x * cos(q) + A.y * sin(q)
}
assert A.scalar_map(B) == {
A.x: B.x * cos(q) - B.y * sin(q),
A.y: B.x * sin(q) + B.y * cos(q),
A.z: B.z
}
assert express(B.x, A, variables=True) == A.x * cos(q) + A.y * sin(q)
assert express(B.y, A, variables=True) == -A.x * sin(q) + A.y * cos(q)
assert express(B.z, A, variables=True) == A.z
assert express(B.x*B.y*B.z, A, variables=True) == \
A.z*(-A.x*sin(q) + A.y*cos(q))*(A.x*cos(q) + A.y*sin(q))
assert express(B.x*B.i + B.y*B.j + B.z*B.k, A) == \
(B.x*cos(q) - B.y*sin(q))*A.i + (B.x*sin(q) +
B.y*cos(q))*A.j + B.z*A.k
assert simplify(express(B.x*B.i + B.y*B.j + B.z*B.k, A,
variables=True)) == \
A.x*A.i + A.y*A.j + A.z*A.k
assert express(A.x*A.i + A.y*A.j + A.z*A.k, B) == \
(A.x*cos(q) + A.y*sin(q))*B.i + \
(-A.x*sin(q) + A.y*cos(q))*B.j + A.z*B.k
assert simplify(express(A.x*A.i + A.y*A.j + A.z*A.k, B,
variables=True)) == \
B.x*B.i + B.y*B.j + B.z*B.k
pytest.raises(TypeError, lambda: express(A.x, 1))
pytest.raises(ValueError, lambda: express(A.i, B, A))
pytest.raises(TypeError, lambda: express(A.i | A.j, B, 1))
pytest.raises(ValueError, lambda: express(1, B, 1))
N = B.orient_new_axis('N', -q, B.k)
assert N.scalar_map(A) == \
{N.x: A.x, N.z: A.z, N.y: A.y}
C = A.orient_new_axis('C', q, A.i + A.j + A.k)
mapping = A.scalar_map(C)
assert mapping[A.x] == (C.x * (2 * cos(q) + 1) / 3 + C.y *
(-2 * sin(q + pi / 6) + 1) / 3 + C.z *
(-2 * cos(q + pi / 3) + 1) / 3)
assert mapping[A.y] == (C.x * (-2 * cos(q + pi / 3) + 1) / 3 + C.y *
(2 * cos(q) + 1) / 3 + C.z *
(-2 * sin(q + pi / 6) + 1) / 3)
assert mapping[A.z] == (C.x * (-2 * sin(q + pi / 6) + 1) / 3 + C.y *
(-2 * cos(q + pi / 3) + 1) / 3 + C.z *
(2 * cos(q) + 1) / 3)
D = A.locate_new('D', a * A.i + b * A.j + c * A.k)
assert D.scalar_map(A) == {D.z: A.z - c, D.x: A.x - a, D.y: A.y - b}
E = A.orient_new_axis('E', a, A.k, a * A.i + b * A.j + c * A.k)
assert A.scalar_map(E) == {
A.z: E.z + c,
A.x: E.x * cos(a) - E.y * sin(a) + a,
A.y: E.x * sin(a) + E.y * cos(a) + b
}
assert E.scalar_map(A) == {
E.x: (A.x - a) * cos(a) + (A.y - b) * sin(a),
E.y: (-A.x + a) * sin(a) + (A.y - b) * cos(a),
E.z: A.z - c
}
F = A.locate_new('F', Vector.zero)
assert A.scalar_map(F) == {A.z: F.z, A.x: F.x, A.y: F.y}